It has long been the customary practice to prepare liquid specimens for microscopic examination by placing a small quantity of specimen on a flat, transparent slide, disposing a small quantity of specimen thereon, as by manual operation of a dropper, then cover the specimen with a thin, transparent cover slip to spread a specimen into a thin film. Reliance is placed on capillary action to retain liquid specimen between the plate and the cover slip, the slide thus prepared and microscopically examined. Such examination often or typically for the purpose of analysis of particulate matter in the liquid, and examination of particulate matter in urine, blood, spinal fluid, sputum, cell cultures, etc. The objective is to spread a specimen to a generally uniform thickness with solid particles therein spaced uniformly on the slide plate.
The volume of specimen will of course vary with the size of the drop or drops applied to a slide, and the force applied between the cover slip and the plate. Distribution of solid particles in the liquid specimen have been typically effected by manual squeezing action, and the thickness of a specimen is dependent upon the quantity of sample disposed on the slide, etc., and can result inerrors of 50% to 200%. Thus, various factors will affect examination results. Dependence is placed upon the skill and experience of a technician. Significant dexterity, manipulation and skill are required to provide a good specimen properly disposed with a cover slip thereon, for proper handling of the slide from the beginning through examination. The process requires substantial expenditure of time by the technician.
The present invention provides a specimen of accurate size, evenly spread for examination, which is quickly provided by disposing a drop of specimen onto a first member, then snapping a second member into engagement with the first member to contain and define a discrete specimen with its thickness determined by a raised ring of accurate dimension extending from the first member and sealingly engaging the second member. Excess specimen liquid is automatically expressed from the specimen chamber thus defined into a reservoir defined between the first and second members. A transparent window is defined in one member to view evenly distributed particulate matter in the specimen.